What is a Food Intolerance Test?

The purpose of a food intolerance test is to determine the foods that a person's body cannot tolerate and digest properly. Some food intolerance is unmistakable, but others require time and testing to diagnose. No one test will be 100 percent accurate. Most medical professionals agree that any number of variables can cause false reads, but performing several tests will produce more accurate results. Intolerance tests can be performed by a medical professional, or the patient can purchase a food intolerance test that can be performed at home.

The hydrogen breath test (HBT) is a food intolerance test used to diagnose the presence of dietary sugars. The patient drinks a solution made up of the very sugars that are suspected of causing symptoms. If the patient cannot digest the sugars in the small intestine, the sugars proceed to the large intestine and are fermented by the bacteria in the colon. After this process occurs, the fermentation produces hydrogen, which is measured through the use of a breath test. The actual breath test takes place several hours after the sugar substance is consumed.

An enzyme-linked immunoserological assay (ELISA) test is a food intolerance test that requires a blood sample. This blood test determines specific levels of antibodies in the blood after the consumption of certain foods and toxins. Certain ELISA tests require blood to be draws, and others require a simple prick to the end of the finger.

The antigen leukocyte cellular antibody test (ALCAT) is a food intolerance test that focuses on the reaction in white blood cells when the patient’s blood is mixed with one of 100 foods tested. The advantage of using this test is that it focuses on the degranulization process instead of looking for a specific immune response. When a food enters a body that cannot tolerate it, the body's immune system will attack it, and the body’s response to these attacks is manifest in food intolerance symptoms. The immune system's attempt to rid itself of the food clearly defines the food as one the patient’s body does not tolerate.

The elimination-then-challenge diet is a food intolerance test that works simply by eliminating the foods that seem to cause intolerance symptoms. The suspected food is removed from the diet for a period of two to four weeks, with the patient symptom-free. The suspected foods can be reintroduced one at a time. The foods should be reintroduced in small portions, followed by a waiting period to insure that the symptoms do not occur again.

The absence of symptoms usually signifies that the food intolerance has been determined. The food can be eliminated from the patient’s diet completely, or the patient can wait for three to four months and then “challenge” the immune system to see if the body has developed a tolerance for the food. Many health professionals and allergist agree that this method is by far the most effective in determining food intolerance.